<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <link rel="stylesheet" href="css_1.html ">
    <style>
        #div1 {
            border:1px solid  red;
            width :200px;
            height :200px;
        }
    </style>
</head>
<body>
 <div id ="div1"></div>

</body>
</html>